1. Field of the Invention
The present invention relates to an integrated circuit. More particularly, the present invention relates to a semiconductor device and a memory having a structure similar to a transistor of a common logic device and a method of operating thereof.
2. Description of Related Art
Among various types of semiconductor devices, memories in which data can be stored, read out or erased and having the advantage that the data stored therein can be retained even after power is cut off has become a memory device widely applied in personal computers and electronic apparatuses.
Generally speaking, in order to reduce the manufacturing cost of the semiconductor device and simplify the process, it gradually becomes a trend to integrate elements of a memory and a logic circuit on the same system, which is also known as an embedded memory. To be specific, in a conventional embedded memory structure, the transistor used as the memory and the transistor used as the logic device are formed on the same system.
However, for the conventional embedded memory, the processes of fabricating the transistor in the memory region and the logic circuit region are two different transistor processes. Since the transistor used as the memory has two poly-Si layers to serve as a control gate and a floating gate, and the transistor used as the logic device has only one poly-Si layer to serve as a gate, the two transistors have different structures. Moreover, the transistor used as the memory and the transistor used as the logic device have different requirements on characteristics. Therefore, the process of manufacturing the embedded memory becomes difficult, thereby influencing the process yield.